If eating and training correctly, no. Certain supplements like creatine can help but I wouldn't say boxers need supplements.
Need, no I don't think so. But getting everything you need from daily food is not an easy task. Besides, when is something called a supplement? If I put olive oil on salad it's dressing, but if I put flaxseed oil in my yogurt it's a supplement. Drinking milk is simply taking in food, whey protein however is a supplement despite coming from the same source.
Be careful if you decide to use any type of protein/muscle builder or similar as some can have an adverse affect on certain individuals. Kostya T became quite unwell after using powder supplements and he aint alone. Remember, anything you put in your mouth has to be broken down via the liver. Natural foods like friut and vegtables are easily taken in so try and get most of your required intake from simple foods. The only thing I'd use is creatine although if you eat alot of red meat I would bypass unless you're struggling hard in the gym.
WTF? Unless we're talking steroids, protein powders (whey mostly) come from normal, natural food. Milk in this case. Fruit and veggies do not contain protein. Seriously that made no sense at all. It's bad because it's powder? Please explain.
Nothing wrong with a quality protein.. Whey is derived from milk, Casein is pretty much the same thing as cottage cheese. Egg protein powder is among the most digestable and absorbable proteins you can get. If protein powders were K.T's problem, It may be that he has a bad milk allergy, but being that he is eastern european, it just doesn't make much sense and not likely since male lactose intolerants tend to specifically NOT be those of European descent. But more Latin Americans, Asians, Africans followed by middle easterners. Protein can be great for helping cut weight in the long run by helping supress the appetite and supplying muscles with needed nutrients and amino acids. Casein proteins are perfect for this. Multi vitamins. You short yourself a little baking soda or baking powder when baking, and your screwed.. Same with nutrition and macro/micro nutrients. They play a vital role. Funny thing MrSmall brings up Magnesium and Zinc. There is a supplement called ZMA that helps increase testosterone which is b vitamin, Zinc and Magnesium based. Men generally don't get enough zinc because it is pretty much cancelled out by calcium. So taking Zinc and Magnesium/zma before bed without any sort of milk or any calcium in food is generally very good FOR MEN.